Scraper means



IN V EN TOR.

iya-

" p 1, 1959 M. J. JALKANEN 'SCRAPER MEANS Filed Dec. 5, 1955 v v w o o 0 N. v y

FIG.

FIG. 2

Unit-6d S 3 Patent SCRAPER MEANS Matti Johannes Jalkanen, Rauma, Finland Application December 5, 1955, Serial No. 551,166 Claims priority, application Finland March 24, 1 955 6 Claims. '15246.5)

The present application relates to scraper means and more particularly to scraper means used to scrape particles or fibers from the top of a strainer surface.

Scraper means of this type are extensively used, for instance in the pulp and paper making industries for removing a layer of solid particles or fibers from the surface of a strainer in order to increase the efficiency of and to provide for the proper operation of such a strainer. One of the difliculties encountered in the operation of such scraper means on top of a strainer, surface is that when the scraper blade moves over the surface of the strainer, some of the particles or fibers tend to wedge themselves between the strainer and the leading edge of the scraper blade and are moved along by the scraper blade on top of the strainer surface. In this case such wedged particles tend to rub against the strainer surface and cause considerable wear on the blade and the strainer surface and increase also the friction between the blade and the strainer surface.

One object of the present invention is to overcome the above mentioned disadvantages. Another object of the present invention is to form the scraper means in such a way that the particles or fibers will move along the leading edge of the scraper blade instead of being wedged between the scraper blade and the strainer.

It is a further object of the present invention to constru ct the scraper means in such a Way that the fibers or particles will move along only part of the leading edge of the scraper blade .so as to reduce the path of these particles or fibers along the strainer surface.

It is yet another object of the present invention to facilitate the movement of the particles and fibers over the scraper blade while the scraper blades move over the strainer surface.

With the above objects in view, the scraper means of the present invention mainly consists in support means, and a scraper blade mounted on the support means for movementin one direction for scraping a surface, the scraper blade having a stepped portion leading in the one direction of movement, the stepped portion including a plurality of leading edge portions, each of the edge portions being inclined to the one direction of movement,

each of the edge portions having one end-leading in the direction of movement and one end trailing in the direction of movement, the leading end of each of the edge portions trailing in the one direction of movement the trail- 7 and an outer end trailing in said direction of movement,

each of the edge portions being also inclined to a line passing through the leading end thereof and extending radially from the axis'of rotation.

2 The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description ofspecificl Fig. 3 is a fragmentary top view of the scraper meanst and Fig. 4 is a fragmentary diagrammatic top view of the scraper blade.

Referring now to the drawings and more particularly to Fig. 1 of the same, the scraper blade 1 is shown"ex-. tending laterally from one side of a shaft 5 and being supported by the shaft for'movement about the shaft axis in one direction indicated by arrow 4 for scraping the surface of a strainer 2. This strainer surface 2, formed for instance by a wire mesh, extends in a plane normal to the shaft axis on the bottom of a cylindrical container or tower 3.

The strainer blade 1 shown in detail in Figs. 2 and 3 has a top surface 6 which is inclined to the plane in which the strainer 2 is located. The blade 1 is rotated in the direction of the arrow 4 and is formed with a stepped portion 8 leading in the direction of the movement. The stepped portion 8 includes a plurality of leading edge portions 711, 7b, 70 which are in contact with the strainer surface and which are inclined to the direction of movee ment indicated by the arrow 4. Each of the edge portions has an inner end and an outer'end, the inner end of the edge portion 7a being designated with 13d and the outer end with 14a, Whereas the inner ends of the edge portions 7b and 7c are respectively designated with 13b and 13c and the outer ends thereof respectively with 14b and 140. It is evident from Fig. 3 that the inner end 13b of the edge portion 7b trails the outer end 14a of the edge portion 7a when the blade is rotated'in the direction of the arrow 4. The edge portions 7a, 7b, 7c are respectively inclined to the direction of movementin dicated by the arrow 4 and also inclined to line r passing respectively through the leading ends 13a, 13b, 13c and'extending radially from the shaft axis. The edge portions 7a, 7b, 70, include with the respective line r an angle which is preferably the same for all of said edge portions. The outer end of each edge portion is connected to the inner end of the adjacent edge portion by connecting edge portion 9, which is formed adjacent the inner or leading end of each leading edge portion with an undercut recess v11 as shown in Fig. 4 so that the leading edge portions overlap slightly. A plurality of guide wings 12 are fixed to the top surface 6 of the scraper blade 1. These guide wings 12 extend, respectively, substantially normal tofthe top surface 6 and substantially parallel to the direction of movement from the inner end of each of the leading edge portions. 7

The scraper means as described above will work as follows:.

When the blade 1 is rotated-by 'the shaft 5 over the surfaceof the strainer 2 most of the particles or fibers forming a cake or layer on'the top of the strainer surface 2 will be lifted by the blade 1 and pass overthe inclined top surface 6 of the same; Some of the fibers will not follow this lifting movement but willtend to sticlg to the leading edge portion :8 of the blade, Such a particle m will be pressed against the leading edgeportiori with a force indicated by the vector R iii-Fig; 4 which is Patented Sept. 1, 1959 j pa'r the di 11 of niovement and due to the inclination of the leading edge portion to this direction of movement, the force indicated by the vector R can a eomponent normal to the edge portion rl arallel tothe edge ortion. The r g the n ction of merwm enent 1 win the part cle to move along a path indicated in 'nlines Fig, 4, are particle will therefore move ff e leading edge portions toward the outer endof thesame and along the connecting edge portion 9' to the iiiiier end of the adjacent leading edge portion. To assure that the particle is not caught in the corner j th the connecting e d portion 9 meets the adjacent leadm g edge portion; the connectin eiid pdrtion 9 is undereut at 11. Ihe particle will therefore become disthe e mi cnng end penis-n, 9 nd will moyenpo: 'urt er rotation in e blade onto the leading edge portion 6f the adjacent blade edge portion and be lifted by the same over thetop surface of the blade.

When a blade accdrding to the present invention is rotated over the strainersur face most of the particles orfi res ing on the strainer surface will be lifted by t p maven over the top surface o'fthe blade ds therear ofthe blade. The guidewings 12 prevent erqblfle tiahsyersefniovement of these lifted particles i d guide, the particles parallelfstreams over the blade. "articles tendin qlstickjotheleading edge of the be moyeda's described above along said stepped leading ed e screens of the blade. Due to the recesses 1.1 provided ineach of thecon necting edge portions 9 or the blade, these particle's will became disengaged frforn the connecting edge portions and come upon further lrotationlofthe blade in contact with the adjacent 1e. e e Pa n 9 tha' ladew a' bf P fieles in; 'fiber's betweeii the strainer'surface and the' leadinaedfgje,pertidnsjisiuer by prevented and the paths of eechffibefr inoviiig along the leading edge portions is thereby 'shor'tened,

"ill be ii "fder'st'ood that ea h of thefelements described above, or two 6r 'mo're together, may also find a iisi'e'fiil applicatidn in other types, of scra er means differiiig'frd n thetype's described above. I

Whilethe 'inventiduhas been illustrated and described embed ejinfaseraper'meansusedjto scrape particles i o the top of a strainersiiriac'e and 'having a pped leading edge, it is not .intended to be limited to "the details, shown, since various modifications and 1 .fiht e i iiayh 'me e i h t departing in any y froin th'e spirit of the resent invention.

) Withoi1't analysis, the foregoing will so fully .J i g t of the present invention that, others, can

applying current knowledge readily. adapt it for varibus applications without omitting features th t, from the ndpd t "orpr'ir art, fairly constitute essential charaeter stics offiiegene'fic 'qr specific aspects of this invenj adap'tja t ions shouldand are in- ,dto be comprehended Within the meaning and fan'gedfiequl alencj'e of the following claims. I F What, is 'cla1r1iiedas'iiew and desired to be secured by lettersjratem is; g Y V t perms "TS comprising, in combination, a shaft;

and fa scraper blade means extendin "laterally from one s'ide jof said shaft and being supported by the same for movement about the shaft "in one direction for scraping a surfacelocated in a first plane ndrmal to 'sIaidaxis, 'sai'd scraper blade'n'ieans'having ast'epped'edge leading in, said one direction of movement, saidfstepped 'i'ricludingfafplufality of leading edge portions all located ina secdnd plane adjachtfto and paralleltosaid first, plane, jeaenjdf said e g persons located in said ee'cond inclined to said onedire'ctio'n of inoveaia se 9 a t j a endas, having n and wleading in said direction of movement and an outer end trailing in said direction of movement, said inner end, of each of said edge portions trailing in said one direc in of movement the outer end of the edge portion adjacent thereto, each of said edge portions being also inclined to a line passing through the leading end thereof and extending radially from said axis, said scraper blade means having a substantially smooth top surface extending rearwardly and inclined at an acute angle to said second plane upwardly from said leading stepped edge.

2. Scraper means comprising; in combination, a shaft; and a scraper blade means extending laterally from one side of said shaft and being supported by the same for movement about the shaft axis in one direction for scraping a surfaceloca'ted in a firstplanenormal to said axis, said scraper blade nieans having a stepped edge leading in said one direction of movement; said stepped portion including a pluralityof leading edge portions all located in a second plane adjacent to and parallel to said first plane, each of said edge portions located in said second plane being inclined to said one direction of movement, each of said .ed'gerportions having an inner end leading in said direction of movement and an, outer end trailing in said direction of movement, said inner end of each of said edge portions trailing in said one direction of movement the outer end of the edge portion adjacent thereto, each of said edge portions being also inclined to a line passing through the leading end thereof and extending radially from said axis, said leading edge portions including respectively with said respective lines equal angles, said scraper blade means having a substantially smooth top surface extending rearwardly and inclined at an acute angle to said second plane upwardly from said leading stepped edge.

'3. Scraper means comprising, in combination, a shaft; and ascraper blade means extending laterally from one side of said shaft and being supported by the same for movement about the shaft axis in one direction for scraping a surface located in a first plane normal to said axis, said scraper blade means having a stepped edge leading in said one direction Iof movement, said stepped edge including a plurality of leading edge portions all located in 'a second plane adjacent to and parallel to said first plane and .a plurality of connecting edge portions, each of said leading edge 'portionslocated in said second plane beingin'c'lined to said one direction of movement, each of said leading edge portions having an inner end leading in said direction 'of movement and an outer. end trailing in said direction of movement, said inner end of each of said leading ed-ge portions trailing in said one direction of movement the outer end of the edge portion adjacent thereto, each-"of 'said leading edge portions being also inclined to a line passing through the leading end thereof and extending radially'from said axis, each of saidcon- 'necting edge po'r'tions connecting the outer end of one of said leading edge portions with the inner end of the leadinged'ge'portion adjacent'saidonefleading edge portion being 'fdrme'd with 'a'n u'ndercut recess adjacent said inner enact therespective adjacent leading edgeportion, said scraper blade means having "a substantially smooth top surfaceextendingrearwardly andinc'lined a't'an acute angle to -said second plane upwardly from said leading 'ste'pped'ed'ge'. v t 4 4. scraper jmean's 'rhprisi'ng, in combination, a shaft; a scraper 'bladefextending laterally'fr'om one sideof 'said shaft and being su ported by the same for movement about the shaft in one direction for scraping a surface l'ocate'd'in a planenorrnaltosaidaxis, said scraper blade havirigia 'topsurfaceandhaving a stepped edge 'leadin-gfi'n said one direction'of'moveinent, said stepped 'dg'eincluding'a pluralitybf'leading edge portions, each of slaid edg portions b'einginclined t'osaid one direction tif mdvemennand adapted to 'extend'along'said plane, eaten-er edge"portions'having"aninner end leading d dire'ction of movemenrana'an ou't'er'end trailing in said idirectio' ofjmov'ement, 's'aidfinner end of each fof saidjedg'efpof ons trailing in said one direction of movement the outer end of theedge portion adjacent thereto, each of said edge portions being also inclined to a line passing through the leading end thereof and extending radially from said axis; and a plurality of guide Wings, each of said guide Wings being fixed to said top surface, extending substantially normal to said top surface and substantially in the direction of said movement of said scraper blade.

5. Scraper means comprisin in combination, a slfaft; a scraper blade extending laterally from one side of said shaft and being supported by the same for movement about the shaft axis in one direction for scraping a surface located in a plane normal to said axis, said scraper blade having a top surface and having a stepped edge leading in said one direction of movement, said stepped portion including a plurality of leading edge portions, each of said edge portions being inclined to said one direction of movement, and adapted to extend along said plane, each of said edge portions having an inner end leading in said direction of movement and an outer end trailing in said direction of movement, said inner end of each of said edge portions trailing in said one direction of movement the outer end of the edge portion adjacent thereto, each of said edge portions being also inclined to a line passing through the leading end thereof and extending radially from said axis; and a plurality of guide wings extending respectively through the inner ends of said edge portions, each of said guide wings being fixed to said top surface, extending substantially normal to said top surface and substantially in the direction of said movement of said scraper blade.

6. Scraper means comprising, in combination, a shaft; a scraper blade extending laterally from one side of said shaft and being supported by the same for movement about the shaft axis in one direction for scraping a surface located in a plane normal to said axis, said scraper blade having a top surface and having a stepped edge leading in said one direction of movement, said stepped edge including a plurality of leading edge portions, said leading edge portions adapted to move in a plane normal to said shaft axis, said top surface being inclined to said plane, each of said edge portions being inclined to said one direction of movement, and adapted to extend along said plane, each of said edge portions having an inner end leading in said direction of movement and an outer end trailing in said direction of movement, said inner end of each of said edge portions trailing in said one direction of movement the outer end of the edge portion adjacent thereto, each of said edge portions being also inclined to a line passing through the leading end thereof and extending radially from said axis; and a plurality of arcuate guide wings, each of said guide wings being fixed to said top surface and having guide faces substantially normal to said top surface and substantially concentric with said shaft.

References Cited in the file of this patent UNITED STATES PATENTS 270,118 Prather Ian. 2, 1883 1,148,547 Smith Aug. 3, 1915 2,117,958 Hershey May 17, 1938 2,540,474 Cox Feb. 6, 1951 2,681,151 Coulter June 15, 1954 FOREIGN PATENTS 511,858 Germany Nov. 5, 1930 512,496 Great Britain Sept. 18, 1939 

